Time code signal transmitting method and time code signal transmitting apparatus

ABSTRACT

The present invention comprises the step of reading a check-receiving data included in a transmitted time code signal and using the read check-receiving data to generate a transmitting side checking data, and the step of attaching the transmitting side checking data to the transmitted time code signal, as a pre-processing step at the time of transmitting the time code signal. The present invention comprises the step of reading the check-receiving data from the received time code signal and using the read check-receiving data to generate a receiving side checking data, and the step of reading the transmitting side checking data from the received time code signal and comparing the read transmitting side checking data to the receiving side checking data, thereby verifying whether or not an error is generated in the received time code signal. In this way, an error can be detected in the time code signal, as a post-processing step after the time code signal is received.

TECHNICAL FIELD

The present invention relates to a method and a device for transmittinga time code signal generated to be attached to a picture signal.

BACKGROUND ART

As a time code signal used in the transmission of a picture signal,there is an LTC (linear time code) signal, which is recorded on a voicefrequency band after being subjected to bi-phase mark modulation. Timecode signals are transmitted in synchronization with picture signals.

In a time code signal, an error (change in data content) may begenerated by a reading failure or transmission failure when the timecode signal is regenerated from a regenerating device or the signal istransmitted. Such an error causes a deterioration in the precision ofthe time code signal. For this reason, it is necessary to detect thegeneration of the error in the time code signal with high accuracy. Whenthe error can be detected, the use of the time code signal can bestopped. The location of the error can also be restored by applying agiven processing to the time code signal.

Hitherto, however, the method or structure for detecting an errorgenerated in time code signals has not been carried out at all, andeffective proposals have not yet been made.

Accordingly, a main object of the present invention is to provide amethod and a device for transmitting a time code signal which can detectan error generated during the transmission of the time code signaleffectively.

DISCLOSURE OF THE INVENTION

The time code signal transmitting method of the present inventioncomprises the step of reading a check-receiving data included in atransmitted time code signal and using the read check-receiving data togenerate a transmitting side checking data; and the step of attachingthe transmitting side checking data to the transmitted time code signalas a pre-processing step at the time of transmitting the time codesignal. Furthermore, The time code signal transmitting method of thepresent invention comprises the step of reading the check-receiving datafrom the received time code signal and using the read check-receivingdata to generate a receiving side checking data; and the step of readingthe transmitting side checking data from the received time code signaland comparing the read transmitting side checking data to the receivingside checking data, thereby verifying whether or not an error isgenerated in the received time code signal as a post-processing stepafter the time code signal is received.

The time code signal transmitting device of the present inventioncomprises a transmitting device for transmitting a time code signal, anda receiving device for receiving the time code signal transmitted by thetransmitting device. The transmitting device comprises a transmittingside checking data generator for reading a check-receiving data includedin the transmitted time code signal and using the read check-receivingdata to generate a transmitting side checking data; and an attachingunit for attaching the transmitting side checking data to thetransmitted time code signal. The receiving device comprises a receivingside checking data generator for reading the check-receiving data fromthe received time code signal and using the read check-receiving data togenerate a receiving side checking data, and a verifying unit forreading the transmitting side checking data from the received time codesignal and comparing the read transmitting side checking data to thereceiving side checking data, thereby verifying whether or not an erroris generated in the received time code signal.

When the time code signal transmitting method or transmitting device isconstructed in this way, an error generated on the time code signal atthe time of regeneration, transmission or the like can be verified withhigh precision by comparing the receiving side checking data generatedfrom the received time code signal to the transmitting side checkingdata read from the received time code signal.

Preferably, the present invention can be applied to a time code signaltransmitting method or transmitting device for transmitting a singletime code signal. Furthermore, the single time code signal is preferablyan LTC signal. In this way, the present invention can be carried out ina system for transmitting a single time code signal. Therefore, an errorcan be verified without complicating a time code signal transmittingsystem.

It is preferable to use, as the check-receiving data, a data recorded ona user's bit area for the time code signal and to further attach thechecking data to the user's bit area for the time code signal. In thisway, an error can be verified in the user's bit area for the time codesignal.

According to the present invention, an error of a time code signal(user's bit area) can be specified and detected in frames whichconstitutes picture signals. In a method and a device for transmitting atime code signal corresponding to a picture signal to which formatconversion in which a change in the number of frames of picture signalsper second is generated is applied, it is necessary that the position,on the signals, of the picture signal after the format conversion isspecified in frames. Therefore, the present invention, which can detectan error in frames, is particularly effective for the case that suchformat conversion is performed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram for illustrating the structure of a time codesignal transmitting device of a preferred embodiment of the presentinvention.

FIGS. 2A and 2B are schematic views illustrating format conversions when24P picture signals are format-converted to 60I picture signals.

FIG. 3 is a schematic view illustrating a format conversion when 10Ppicture signals are format-converted to 60I picture signals.

FIG. 4 is a schematic view illustrating the configuration of a user'sbit area for time code signals (LTC signals) used in the presentinvention.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring to the drawings, the preferred embodiment of the presentinvention is described in detail hereinafter. FIG. 1 is a block diagramillustrating the structure of a time code signal transmitting device ofthe preferred embodiment of the present invention. In the presentembodiment, it is assumed that format conversion is carried out. In thepresent embodiment, the present invention is carried out in the devicefor transmitting time code signals corresponding to picture signalsafter the format conversion. More specifically, in the presentembodiment, it is assumed that a picture signal in a progressive formatof 24 frames/second (hereinafter referred to as a 24P format)(hereinafter referred to as a 24P picture signal) is primarily convertedto a picture signal in an interlace format of 30 frames/second(hereinafter referred to as a 60I format) (hereinafter referred to as a60I picture signal).

In the present embodiment, the present invention is carried out in atime code signal transmitting device 1 for transmitting a time codesignal corresponding to a picture signal after the format primaryconversion (60I picture signal) when such a conversion is carried out,or in a secondary conversion (reverse conversion) of the format usingthe transmitted time code.

The time code signal transmitting device 1 has a transmitting device 2and a receiving device 3. First, the structure of the transmittingdevice 2 is described.

The transmitting device 2 has a time code data reader 4, a renewal framedata generator 5, a time code auxiliary data generator 6, a sequencenumber data generator 7, a transmitting side checking data generator 9,an LTC signal generator 10, and a transmitter 11.

The time code data reader 4 reads a time code data “It” generatedoutside the time code signal transmitting device 1. The time code datareader 4 outputs the read time code data “It” to the renewal frame datagenerator 5, the time code auxiliary data generator 6, the sequencenumber data generator 7, and the LTC signal generator 10.

The renewal frame data generator 5, the time code auxiliary datagenerator 6, and the sequence number data generator 7 generate variousattachment data Ia from the time code data “It” which the time code datareader 4 reads. The attachment data Ia are data stored in a user's bitarea 20 for LTC signals (time code signals).

The attachment data Ia include a renewal frame data Ib, a time codeauxiliary dat Ic, and a sequence number data Id. The renewal frame dataIb is generated in the renewal frame data generator 5. The time codeauxiliary data Ic, is a data including a frame rate data (the numericaldata of a frame rate) Ic₁, a data Ic₂ for distinguishinginterlace/progressive formats from each other, and other auxiliary dataIc₃. The time code auxiliary data Ic, having such a construction isgenerated in the time code auxiliary data generator 6. The sequencenumber data Id is generated in the sequence number data generator 7.

The generators 5, 6 and 7 outputs the generated various attachment dataIa, to the LTC signal generator 10 and the transmitting side checkingdata generator 9.

The transmitting side checking data generator 9 generates a transmittingside checking data Dt, from the inputted attachment data Ia (the renewalframe data Ib, the time code auxiliary data Ic, and the sequence numberdata Id), and then outputs the data DT to the LTC signal generator 10.That is, the transmitting side checking data generator 9 converts theinputted attachment data Ia into check-receiving data, so as to generatethe transmitting side checking data Dt.

The LTC signal generator 10 generates an LTC signal data, which is atime code signal, on the basis of the time code signal It, theattachment data Ia (the renewal frame data Ib, the time code auxiliarydata Ic, and the sequence number data Id), and the transmitting sidechecking data Dt. The LTC signal generator 10 outputs the generated LTCsignal to the transmitter 11. The transmitter 11 transmits the inputtedLTC signal to the receiving device 3. The method of the transmission isnot particularly limited. The transmitter 11 transmits the LTC signal tothe receiving device 3, for example, through cable transmission.

The following describes the structure of the receiving device 3. Thereceiving device 3 has a receiver 12, a check-receiving data reader 13,a receiving side checking data generator 14, a checking data reader 15,and a verifying unit 16.

The receiver 12 receives the LTC signal transmitted from thetransmitting device 2. The receiving side check-receiving data reader 13reads out the attachment data Ia from the user's bit area 20 for thereceived LTC signals and then outputs the data Ia to the receiving sidechecking data generator 14.

The receiving side checking data generator 14 uses the read attachmentdata Ia to carry out an operation on the basis of a given checkingequation, thereby generating a receiving side checking data Dr. Thechecking equation used in the receiving side checking data generator 14is the same as used in the transmitting side checking data generator 9.

The checking data reader 15 reads out the transmitting side checkingdata Dt from the received LTC signal. The verifying unit 16 compares thetransmitting side checking data Dt to the receiving side checking dataDr, thereby verifying whether or not an error is generated in the user'sbit area 20 for the received LTC signal.

In the figure, reference number 17 represents an LTC signal outputterminal for outputting the LTC signal received by the receiver 12outwards from the receiving device 3; and 18 represents a verifiedresult output terminal for outputting the verified result from theverifying unit 16 outwards from the receiving device 3.

In the present embodiment, the transmitting side checking data generator9 constitutes an example of a transmitting side checking data generator.The LTC signal generator 10 constitutes an example of an attaching unit.The check-receiving data reader 13 and the receiving side checking datagenerator 14 constitute a receiving side checking data generator. Thechecking data reader 15 and the verifying unit 16 constitute a verifyingunit. However, these constitutions are examples for carrying out thepresent invention. Thus, the present invention may have any structurethat can exhibit functions described in the claims.

The following describes the attachment data Ia. The attachment data Iaare data effective for a time code signal transmitting form as describedbelow.

By recent developments in picture techniques, the format conversion ofpicture signals can be attained. For example, a picture signal in a 24Pformat can be converted to a picture signal in a 60I format. In the casewhere format conversion is carried out, in general, the number of framesper second increases or decreases. That is, by format conversionprocessing, the number of picture data which constitute each frame(hereinafter referred to as frame picture data) in picture signalsincreases or decreases. Therefore, at least one frame picture data amongthe respective frame picture data which constitute the picture signalbefore the conversion is deleted or is recorded in an overlap state onthe picture signal after the conversion.

In the case of carrying out format conversion in such a way, reverseconversion to the format before the conversion is carried out ifnecessary. The reason for this is as follows.

In picture processing devices which are generally used, such as anon-linear editor, image processing can be carried out only in awide-use format (for example, a 60I format or a 30P format) in manycases. On the other hand, in the case of converting a picture signal ina wide-use format (for example, a 60I picture signal or a 30P picturesignal) to a picture signal in a non-wide-use format, it is necessary toconvert the picture signal reversely to the format before the conversionin order that the picture signal will be image-processed in theabove-mentioned general picture processing devices.

In the case of subjecting a picture signal converted into such a formatthat the number of frames per second increases to image processing(non-linear edition) or in other cases, it is effective to convert thepicture signal reversely to the picture signal in the format before theconversion. This is based on the following reason or some other reasons:returning to the picture format before the conversion makes it possibleto decrease record capacity at the time of the edition.

In the following description, such reverse conversion is named secondaryconversion, and is distinguished from primary conversion, which iscarried out at the first stage. Picture data are composed of framepicture data arranged successively along time series. In the case of aninterlace picture signal, the frame picture data thereof is composed ofa pair of field picture data.

In order to return a picture signal after primary conversion(hereinafter referred to as a primary conversion picture signal)precisely to the original picture by secondary conversion, it isnecessary to grasp precisely the arrangement order of picture data inthe primary conversion picture signal. The following describes thereason for this. Herein, the reason is described, giving, as an example,a conversion form at the time of converting 24P picture signalsprimarily to 60I picture signals or a conversion form at the time ofconverting 10P picture signals primarily to 60I picture signals.Needless to say, however, the reason is also true for other formatconversions.

FIGS. 2A and 2B illustrate conversion formats at the time of converting24P picture signals primarily to 60I picture signals. FIG. 3 illustratesa conversion form for converting 10P picture signals primarily to 60Ipicture signals.

First, a case in which 24P picture signals are primarily converted to60I picture signals is described, referring to FIG. 2A. FIG. 2Aillustrates a conversion technique called the 2:3:2:3 pull-downtechnique. 24P frame picture data corresponding to four frames in 24Ppicture signals are primarily converted to 60I picture signals, wherebya data corresponding to one frame increases so that 60I frame picturedata corresponding to five frames are generated.

In the case where the above-mentioned primary conversion (24P→60I) iscarried out in the 2:3:2:3 pull-down conversion technique about the twopicture signals having a format difference as described above,processing as described below is carried out.

First, from frame picture data (A), (B), (C) and (D), which aresuccessively arranged on a time base in 24P picture signals, 24I framepicture data (Ao|Ae), (Bo|Be), (Co|Ce) and (Do|De) in 24I picturesignals (interlace picture signals of 24 frames/second) are taken out,wherein “o” represents a first field, and “e” represents a second field.

Furthermore, from the taken-out 24I frame picture data (Ao|Ae), (Bo|Be),(Co|Ce) and (Do|De), 60I frame picture data (Ao|Ae), (Bo|Be), (Bo|Ce),(Co|De), and (Do|De) corresponding to five frames of 60I picture signalsare generated. By repeating such a generation (conversion) operation forevery four frames in the 24P format, the 24P picture signals areprimarily converted to 60I picture signals.

At this time, among the respective 24I field picture data (Ao), (Ae),(Bo), (Be), (Co), (Ce), (Do) and (De) which constitute the taken-out 24Iframe picture data (Ao|Ae), (Bo|Be), (Co|Ce) and (Do|De), two 24I fieldpicture data (Bo) and (De), which total to one frame, are used induplication. The 24I field picture data (Bo) and (De) used induplication and positions where they are inserted are decided inadvance. Furthermore, arrangement positions of the respective 24I fieldpicture data (Ao), (Ae), (Bo), (Be), (Co), (Ce), (Do) and (De) includingthe 24I field picture data (Bo) and (De) used in duplication are alsodecided in advance. FIG. 2A illustrates the order of the insertingarrangement thereof. Hereinafter, such an arrangement-order-rearrangingrule in primary conversion is referred to as the primary conversionrule.

The above-mentioned description with reference to FIG. 2A is about aconversion technique called the 2:3:2:3 pull-down conversion technique.In the case where 24P picture signals are primarily converted to 60Ipicture signals, there is also a conversion technique called the 2:3:3:2pull-down conversion technique as shown in FIG. 2B. In the 2:3:3:2pull-down conversion technique, two 24I field picture data (Bo) and (Ce)are used in duplication. The 24I field picture data (Bo) and (Ce) usedin duplication and positions where they are inserted are decided inadvance. Furthermore, arrangement positions of the respective 24I fieldpicture data (Ao), (Ae), (Bo), (Be), (Co), (Ce), (Do) and (De) includingthe 24I field picture data (Bo) and (Ce) used in duplication are alsodecided in advance. FIG. 2B illustrates the order of the insertingarrangement thereof. The 2:3:3:2 pull-down conversion technique has onlya minor difference from the 2:3:2:3 pull-down conversion technique infield combination at the time of conversion.

The following describes a case in which 10P picture signals areprimarily converted to 60I picture signals. 10I frame picture datacorresponding to one frame in 10I picture signals are primarilyconverted to 60I picture signals, whereby data corresponding to twoframe increase so that 60I frame picture data corresponding to threeframes are generated.

Specifically, from respective 10P frame picture data (A) in 10P picturesignals, frame picture data (Ao|Ae) in 10I picture signals (interlacepicture signals of 10 frames/second) are first taken out.

Furthermore, from the taken-out 10I picture data (Ao|Ae), 60I framepicture data (Ao|Ae), (Ao|Ae) and (Ao|Ae) corresponding to three framesof 60I picture signals are generated. Specifically, by duplicating thesame 10I frame picture data (Ao|Ae) repeatedly by three frames, 60Iframe picture data (Ao|Ae), (Ao|Ae) and (Ao|Ae) corresponding to threeframes are generated. By repeating such a generation (conversion)operation for every frame in the 10P format, the 10P picture signals areprimarily converted to 60I picture signals. FIG. 3 illustrates the orderof the inserting arrangement thereof.

In order to convert each kind of the primary conversion picture signalsdescribed above secondarily to the original picture signal with highprecision, it is necessary to cause each of the frames in the primaryconversion picture signals to correspond to each of frames in picturesignals after the secondary conversion with high precision. In order tocause such correspondence, it is important to obtain, with precision,frame positions where a change in picture data is generated in theprimary conversion picture signals at the time of the secondaryconversion.

In the time code signal transmitting device 1 of the present embodimentfor transmitting time code signals corresponding to primary conversionpicture signals (hereinafter referred to as primary conversion time codesignals), the following attachment data Ia are attached to the user'sbit area 20 for the transmitted time code signals. The user's bit area20 is also called a binary group, and is set into 32 bits out of 64 bitsof data bits of SMPTE/EBU time code signals. A renewal frame data Ib isgenerated correspondingly to an interlace format, for example, in thefollowing manner.

In the time code signal transmitting device 1, a data showing a frameposition where a change in picture data is generated in primaryconversion is used as the renewal frame data Ib, and the renewal framedata Ib selected in this way is attached to the user's bit area 20 forthe primary conversion time code signal. The renewal frame data is anexample of data showing the frame position of a picture signal wherein achange in picture data is generated by format conversion.

The renewal frame data Ib is generated correspondingly to an interlaceformat, for example, in the following manner. In the case where a changeis generated in the picture data in the first field in the frame, arenewal frame data Ib(2) is attached to the user's bit area 20 for theprimary conversion time code signal corresponding to the frame. In thecase where a change is generated in the picture data in the second fieldin the frame, a renewal frame data Ib(1) is attached to the user's bitarea 20 for the primary conversion time code signal corresponding to theframe. In the case where a change is not generated in any picture datain the frame, a renewal frame data Ib(0) is attached to the user's bitarea 20 for the primary conversion time code signal corresponding to theframe.

When there is used the primary conversion time code signal to which therenewal frame data Ib corresponding to the state of the primaryconversion of each frame is attached, primary conversion picture signalscan be secondarily converted with high precision.

First, the function of the renewal frame data Ib and secondaryconversion operation using the data are described giving, as an example,a case of returning picture signals obtained by converting 24P picturesignals primarily to 60I picture signals to 24P picture signals bysecondary conversion. Herein, the secondary conversion operation isdescribed giving the 2:3:2:3 pull-down conversion technique as anexample.

As shown in FIG. 2A, in this case, a change in picture data isgenerated, in the 60I picture signals after the primary conversion, asfollows. In the frame (Ao|Ae), the picture data in the first fieldthereof is changed to the frame (not illustrated) immediately before theframe (Ao|Ae). In the frame (Bo|Be), the picture data in the first fieldthereof is changed to the frame (Ao|Ae), which is immediately before theframe (Bo|Be). In the frame (Bo|Ce), the picture data in the secondfield thereof is changed to the frame (Bo|Be), which is immediatelybefore the frame (Bo|Ce). In the frame (Co|De), the picture data in thesecond field thereof is changed to the frame (Bo|Ce), which isimmediately before the frame (Co|De). In the frame (Do|De), no picturedata is changed to the frame (Co|De), which is immediately before theframe (Do|De).

On the basis of such changes in the picture data, in this time codesignal transmitting device 1, the following renewal frame data Ib areattached to time code signals (LTC signals) corresponding to the primaryconversion picture signals (60I picture signals). A renewal frame dataIb(2) is attached to the user's bit area 20 for the time code signalcorresponding to each of the frames (Ao|Ae) and (Bo|Be). A renewal framedata Ib(1) is attached to the user's bit area 20 for the time codesignals corresponding to the frames (Bo|Ce) and (Co|De). A renewal framedata Ib(0) is attached to the user's bit area 20 for the time codesignal corresponding to the frames (Do|De).

The (numerical information) attached to each of the renewal frame dataIb means the following. (2) means that: in the present frame a change inthe picture data in the first field thereof is generated; therefore, insecond conversion the picture signals in the first and second fieldswhich constitute the frame are used to generate a frame picture data.

(1) means that: in the present frame a change in the picture data in thesecond field thereof is generated; therefore, in second conversion thefield picture data in the second field which constitutes the frame andthe field picture data in the first field in the next frame are used togenerate a frame picture data.

(0) means that: in the present frame the picture data is not changedfrom the previous frame; therefore, in second conversion it isunnecessary to generate any frame picture data from the field picturedata which constitutes this frame.

The above has described the second conversion operation, giving the2:3:2:3 pull-down conversion technique as an example. However, needlessto say, in the 2:3:3:2 pull-down conversion technique illustrated inFIG. 2B, the same secondary conversion operation is carried out.

In the case where the renewal frame data Ib attached to time codesignals are used to convert primary conversion picture signals (60Ipicture signals) secondarily to 24P picture signals, the followingprocessing is carried out to the primary conversion picture signals (60Ipicture signals).

In the frame (Ao|Ae), a frame picture data (A) of a 24P picture signalis generated from the field picture data (Ao) in the first field wherethe picture data is changed and the second field picture data (Ae),which is next to the (Ao) on time. The generation of the frame picturedata (A) is based on the reading of the renewal frame data Ib(2)attached to the user's bit area 20 for the time code signalcorresponding to the frame.

In the frame (Bo|Be), a frame picture data (B) of a 24P picture signalis generated from the field picture data (Bo) in the first field wherethe picture data is changed and the second field picture data (Be),which is next to the (Bo) on time. The generation of the frame picturedata (B) is based on the reading of the renewal frame data Ib(2).

In the frame (Bo|Ce), a frame picture data (C) of a 24P picture signalis generated from the field picture data (Ce) in the second field wherethe picture data is changed and the first field picture data (Co) in theframe (Co|De), which is next to the (Ce) on time. The generation of theframe picture data (C) is based on the reading of the renewal frame dataIb(1).

In the frame (Co|De), a frame picture data (D) of a 24P picture signalis generated from the field picture data (De) in the second field wherethe picture data is-changed and the first field picture data (Do) in theframe (Do|De), which is next to the, (De) on time. The generation of theframe picture data (D) is based on the reading of the renewal frame dataIb(1).

In the frame (Do|De), no frame picture data of a 24P picture signal isgenerated from the picture data in this frame. The generation of noframe picture signal is based on the reading of the renewal frame dataIb(0).

By carrying out such secondary conversion, the primary conversionpicture signals (60I picture signals) can be secondarily converted to24P picture signals with high precision.

The following describes the content of the renewal frame data Ib andsecondary conversion operation, giving, as an example, a case ofreturning picture signals obtained by converting 10P picture signalsprimarily to 60I picture signals to 10P picture signals by secondaryconversion.

As shown in FIG. 3, in this case, a change in picture data is generated,in the primary conversion picture signals (60I picture signals), asfollows. In the first frame (Ao|Ae), the picture data in the first fieldthereof is changed to the frame (not illustrated) immediately before theframe (Ao|Ae). In each of the second and third frames (Ao|Ae) and(Ao|Ae), no picture data are changed to the frame immediately before theframe.

On the basis of such changes in the picture data, in this time codesignal transmitting device 1, the next renewal frame data Ib is attachedto the user's bit area 20 for time code signals corresponding to theprimary conversion picture signals (601 picture signals). A renewalframe data Ib(2) is attached to the user's bit area 20 for the time codesignal corresponding to the first frame (Ao|Ae). A renewal frame dataIb(0) is attached to the user's bit area 20 for each of the time codesignals corresponding to the second and third frames (Ao|Ae) and(Ao|Ae).

In the case where the renewal frame data Ib attached to the time codesignals are used to convert the primary conversion picture signals (60Ipicture signals) secondarily to 10P picture signals, the followingprocessing is carried out to the primary conversion picture signals (60Ipicture signals).

In the first frame (Ao|Ae), a 10P frame picture data (A) is generatedfrom the field picture data (Ao) in the first field where the picturedata is changed and the second field picture data (Ae), which is next tothe (Ao) on time, on the basis of the reading of the renewal frame dataIb(2) attached to the user's bit area 20 for the time code signalcorresponding to the frame. In the second and third frames (Ao|Ae) and(Ao|Ae), no frame picture data are generated from the picture data inthese frames on the basis of the reading of the renewal frame dataIb(0).

By carrying out such secondary conversion, the primary conversionpicture signals (60I picture signals) can be secondarily converted to10P picture signals with high precision.

In order to use the renewal frame data Ib to carry out theabove-mentioned secondary conversion, it is necessary to generateconversion periodic signals for the primary conversion picture signals.The conversion periodic signals are signals showing, when originalpicture signals are converted to primary conversion picture signals, thevariable period of the picture data. In the case where 24P picturesignals are primarily converted to 60I picture signals, the conversionperiodic signals have a five-frame period. In the case where 10P picturesignals are primarily converted to 60I picture signals, the changeperiodic signals have a three-frame period. On the side of a device forcarrying out secondary conversion (image processing device), conversionperiodic signals can be made on the basis of the renewal frame data Ibattached to time code signals. The reason why conversion periodicsignals can be made on the basis of the renewal frame data Ib is asfollows. About the renewal frame data Ib, the data are repeated inaccordance with the conversion period at the time of primary conversion.Therefore, by detecting the repetition period, conversion periodicsignals can be made.

In the time code signal transmitting device 1 of the present embodiment,another attachment data Ia is further attached to the user's bit area 20for time code signals. In the case where 24P picture signals areprimarily converted to 60I picture signals or 30P picture signals or inother cases, a periodic sequence in which five frames of the primaryconversion picture signals (60I picture signals or 30P picture signals)are set to one period is repeatedly carried out. As described above,such a periodic sequence is called the 2:3:2:3 pull-down processing or2:3:3:2 pull-down processing (see FIGS. 2A and 2B about details of thesepull-down processings).

In the primary conversion picture signals subjected to these pull-downprocessings, the same primary conversion processing is repeatedlycarried out for every five frames. Therefore, the primary conversionpicture signals can be secondarily converted with precise when it ispossible to grasp which of period positions in the five-frame periodeach of the frames in the primary conversion picture signals (60Ipicture signals or 30P picture signals) is present in. Thus, in the timecode signal transmitting device 1 of the present embodiment, fivesequence number data Id(00), (01), (02), (03) and (04) are successivelyattached to time code signals corresponding to the primary conversionpicture signals (60I picture signals or 30P picture signals), so as tocorrespond to the respective frame positions.

Specifically, sequence number data Id of (00 01 02 03 04 00 01 02 03 04. . . ) are produced to correspond to values (00 01 02 03 04 05 06 07 0809 10 11 . . . 27 28 29 00 . . . ) of the frame places of time codes inthe primary conversion picture signals (60I picture signals or 30Ppicture signals). The produced sequence number data Id are attached tothe user's bit area 20 for time code signals in the state that the dataId are caused to correspond to positions of the respective frames of thetime code signals.

The sequence number data Id is calculated as the remainder obtained bydividing any time code by an integer of 5. This is a calculating methodbased on the matter that each of the above-mentioned pull-downprocessings is a processing in which format conversion processing isrepeated for every five frames.

In the primary conversion picture signals (60I picture signals), thesequence number data Id have the following primary meaning. In each ofthe frames, in the primary conversion picture signals (60I picturesignals) corresponding to the sequence number data Id(00) and Id(01), apicture data change is generated in the field picture data in the firstfield thereof. In each of the frames, in the primary conversion picturesignals (60I picture signals) corresponding to the sequence number dataId(02) and Id(03), a picture data change is generated in the fieldpicture data in the second thereof. In each of the frames, in theprimary conversion picture signals (60I picture signals) correspondingto the sequence number data Id(04), a picture data change is notgenerated in the field picture data in any field thereof. The sequencenumber data Id is an example of data showing a synchronized statebetween the frame conversion period and time code advance at the time offormat conversion.

In the case of using the time code signals to which the sequence numberdata Id having such a meaning are attached to convert the primaryconversion picture signals (60I picture signals) secondarily to 24Ppicture signals, the following processing is carried out to the primaryconversion picture signals (60I picture signals).

In the frame (Ao|Ae), the following processing is carried out on thebasis of the reading of the sequence number data Id(00) attached to theuser's bit area 20 for the time code signal corresponding to theposition of the frame. In this case, a frame picture data (A) isgenerated from the field picture data (Ao) in the first field in theframe where a picture data change is generated, and the second fieldpicture data (Ae), which is next thereto in time.

In the frame (Bo|Be), the following processing is carried out on thebasis of the reading of the sequence number data Id(01) attached to theuser's bit area 20 for the time code signal corresponding to theposition of the frame. In this case, a frame picture data (B) isgenerated from the field picture data (Bo) in the first field in theframe where a picture data change is generated, and the second fieldpicture data (Be), which is next thereto in time.

In the frame (Bo|Ce), the following processing is carried out on thebasis of the reading of the sequence number data Id(02) attached to theuser's bit area 20 for the time code signal corresponding to theposition of the frame. In this case, a frame picture data (C) isgenerated from the field picture data (Ce) in the second field in theframe where a picture data change is generated, and the first picturedata (Co) in the frame (Co|De), which is next thereto in time.

In the frame (Co|De), the following processing is carried out on thebasis of the reading of the sequence number data Id(03) attached to theuser's bit area 20 for the time code signal corresponding to theposition of the frame. In this case, a frame picture data (D) isgenerated from the field picture data (De) in the second field in theframe where a picture data change is generated, and the first fieldpicture data (Do) in the frame (Do|De), which is next thereto in time.

In the frame (Do|De), on the basis of the reading of the sequence numberdata Id(04) attached to the user's bit area 20 for the time code signalcorresponding to the position of the frame, no frame picture data isgenerated from the picture data in this frame (Do|De).

By carrying out such secondary conversion, the 60I picture signals afterbeing subjected to the primary conversion can be secondarily convertedto 24P picture signals with high precision.

In the case where 24P picture signals are primarily converted to 30Ppicture signals and then the 30P picture signals are reversely convertedto 24P picture signals by secondary conversion, each of theabove-mentioned pull-down processings is basically performed, asdescribed above. Therefore, the above-mentioned sequence number data Idare effective. Thus, by applying secondary conversion to the primaryconversion picture signals (30P picture signals) on the basis of thesequence number data Id, the 30P picture signals can be preciselyreturned to 24P picture signals.

As described above, the sequence number data Id are auxiliary data whichare effective when picture signals to which each of the above-mentionedpull-down processings is applied at the time of primary conversion (24ppicture signals→60I picture signals or 24P picture signals→30P picturesignals) are secondarily converted (60I picture signals→24P picturesignals, or 30P picture signals 24P picture signals). Consequently, thedata Id are not effective when other picture signals to which each ofthe above-mentioned pull-down processings is not applied at the time ofprimary conversion (10P picture signals→60I picture signals) aresecondarily converted. For this reason, no sequence number data Id aregiven to time code signals which are attached to other primaryconversion picture signals to which each of the above-mentionedpull-down processings is not applied at the time of primary conversion.In this case, the data of NO INFO (for example, Fh in the 16 numbersystem representation) is attached to the user's bit area 20.

The renewal frame data Ib or the sequence number data Id described aboveare recorded on the user's bit area 20 for time code signals transmittedby the time code signal transmitting device 1. The following describesan example of the configuration of data stored in the user's bit area 20for the transmitted time code signals with reference to FIG. 4.

The user's bit area 20 has first to eighth recording areas 20 ₁ to 20 ₈.In the first recording area 20 ₁ and the second recording area 20 ₂, atransmitting side checking data Dt is stored. The third memory area 20 ₃is a reserve area, and is not particularly used as a data-storing areain the present invention. In the fourth recording area 20 ₄, a sequencenumber data Id is stored. In the fifth memory area 20 ₅ and the sixthrecording area 20 ₆, a frame rate data Ic₁ is stored. In the seventhmemory area 20 ₇, a data Ic₂ for distinguishing interlace/progressiveformats from each other and a data Ic₃ for distinguishing the 2:3:2:3technique/the 2:3:3:2 technique from each other in pull-down processingare stored. In the eighth memory area 20 ₈, a renewal frame data Ib andsome other auxiliary data Ic₃ are stored.

The following describes an example of the method of calculating theabove-mentioned transmitting side checking data Dt and receiving sidechecking data Dr.

The data in the first to eighth recording areas 20 ₁ to 20 ₈ whichconstitute the user's bit area 20 for transmitted time code signals arerepresented by a1 to a8, in sequence. Each of the transmitting sidechecking data Dt and the receiving side checking data Dr is calculatedin the 16 number system from the following equation (1):Dt, Dr=((00h+A34+A56+A78)&FFh)XOR 55h  (1)A34=(a3<<4)+a4A56=(a5<<4)+a6A78=(a7<<4)+a8

wherein XOR: an operator for performing exclusive logical OR operation,

-   -   <<: an operator for performing bit shift to a high-order digit,    -   &: an operator for performing logical AND operation, and    -   h means a numerical value in the 16 number system.

The recording areas 20 ₁ and 20 ₂ are areas in which the transmittingside checking data Dt is stored, it is impossible to use such thereceiving side checking data Dt as a variable to calculate thetransmitting side checking data Dt or the receiving side checking dataDr. For this reason, in the equation (1), variables corresponding to thefirst and second recording areas 20 ₁ and 20 ₂ are set to 00h.

When the above-mentioned equation (1) is used, the transmitting sidechecking data Dt and the receiving side checking data Dr are calculated,for example, as follows: when a1=*, a2=*, a3=C, a4=D, a5=1, a6=2, a7=3and a8=4, they are:

$\begin{matrix}{{Dt},{{Dr} = {\left( {{\left( {{00h} + {CDh} + {12h} + {34h}} \right)\mspace{11mu}\&}\mspace{14mu}{FFh}} \right){XOR}\mspace{14mu} 55h}}} \\{= {\left( {{{113h}\mspace{11mu}\&}\mspace{14mu}{FFh}} \right){XOR}\mspace{14mu} 55h}} \\{= {46h}}\end{matrix}$

The following describes a method of using the time code signaltransmitting device 1 of the present embodiment to transmit time codesignals. Herein, the method is described on the assumption that timecode signals corresponding to picture signals which are format-convertedfrom 24P picture signals to 60I picture signals by primary conversionprocessing are transmitted.

First, an operation performed by the receiving device 2 is described.First, a time code data It generated outside the time code signaltransmitting device 1 is read out in the time code data reader 4. Thetime code data It read out herein is a time code data It correspondingto a picture signal format-converted to a 60I picture signal by primaryconversion. The time code data reader 4 outputs the read time code dataIt to the renewal frame data generator 5, the time code auxiliary datagenerator 6 and the sequence number data generator 7.

The renewal frame data generator 5 generates the above-mentioned renewalframe data Ib from the inputted time code data It to output the data tothe LTC signal generator 10 and the transmitting side checking datagenerator 9.

The time code auxiliary generator 6 generates time code auxiliary dataIc (a frame rate data Ic₁, an interlace/progressive formatdistinguishing data Ic₂, and other auxiliary data Ic₃) from the inputtedtime code data It to output the data to the LTC signal generator 10 andthe transmitting side checking data generator 9.

The sequence number data generator 7 generates the above-mentionedsequence number data Id from the inputted time code data It to outputthe data to the LTC signal generator 10 and the transmitting sidechecking data generator 9.

The transmitting side checking data generator 9 uses the inputtedrenewal frame data Ib, time code auxiliary data Ic and sequence numberdata Id as checking data to subject these checking data tochecking-processing based on a given checking equation (an examplethereof being described above), so as to generate a transmitting sidechecking data Dt. The transmitting side checking data generator 9outputs the generated transmitting side checking data Dt to the LTCsignal generator 10.

The LTC signal generator 10 generates an LTC signal, which is a timecode signal, on the basis of the inputted time code data It, attachmentdata Ia (renewal frame data Ib, time code auxiliary data Ic, andsequence number data Id) and transmitting side checking data Dt. Herein,the attachment data Ia and the transmitting side checking data Dt arestored in the user's bit area 20 for the LTC signal. The manner of thestorage has been described above with reference to FIG. 4, anddescription thereof is omitted here.

The LTC signal generated in the LTC signal generator 10 is transmittedfrom the transmitter 11 to the receiving device 3.

The following describes an operation performed by the receiving device3. First, the LTC signal received by the receiver 12 passes, as it is,through the receiver 12 so as to be outputted from the LTC signal outputterminal 17 to the outside. At this time, the LTC signal is supplied tothe check-receiving data reader 13 and the checking data reader 15.

The check-receiving data reader 13 reads out a check-receiving data fromthe LTC signal inputted from the receiver 12. The check-receiving datais read out, about each frame of LTC signals, from the user's bit area20 thereof. Specifically, the attachment data Ia, which is stored in theuser's bit area 20 for each of the frames of LTC signals, is read out asthe check-receiving data.

The check-receiving data (attachment data Ia) read out in thecheck-receiving data reader 13 is supplied to the receiving sidechecking data generator 14. In the receiving side checking datagenerator 14, the same checking equation as set in the transmitting sidechecking generator 9 is set and memorized beforehand. The receiving sidechecking data generator 14 applies an operation based on the memorizedchecking equation to the supplied data for receiving check (attachmentdata Ia). An example of the checking equation is the above-mentionedequation (1).

The receiving side checking data generator 14 outputs the operationresult, as a receiving side checking data Dr, to the verifying unit 16.

On the other hand, the checking data reader 15 reads out thetransmitting side checking data Dt from the user's bit area 20 for theLTC signal received in the receiver 12. The receiving side checking dataDt is read out in frames of LTC signals. The checking data reader 15supplies the read transmitting side checking data Dt to the verifyingunit 16.

The verifying unit 16 compares the receiving side checking data Drsupplied from the receiving side checking generator 14 to thetransmitting side checking data Dt supplied from the checking datareader 15 in frame. When the two data are consistent with each other,the verifying unit 16 determines that, in the received LTC signal, noerror is present in the data in the user's bit area 20 in the positionof the frame. On the other hand, when the two data are not consistentwith each other, the verifying unit 16 determines that, in the receivedLTC signal, some errors are present in the data in the user's bit area20 in the position of the frame. The verifying unit 16 outputs theerror-detected result from the verified result output terminal 18 to theoutside of the receiving device 3.

The time code signal transmitting device of the present embodimentdetects whether or not an error is generated in the user's bit area 20for the LTC signal which is being transmitted by the error-detectingoperation described above.

Since the time code signal transmitting device 1 compares thetransmitting side checking data Dt to the receiving side checking dataDr for each of the frames, an error in the user's bit area 20 for LTCsignals can be specified and detected in frame. In the case ofperforming format conversion, it is particularly effective that an errorcan be detected in frame. When primary conversion in which the number offrames per second increases or decreases is performed, frame data whichis effective in secondary conversion are scattered in frame data whichconstitute the primary conversion picture signals. Therefore, the timecode signal transmitting device 1 which can detect an error in frame isparticularly effective for carrying out highly precise secondconversion.

In the above-mentioned embodiment, the sequence number data Id and therenewal frame data Ib are attached to the user's bit area 20, therebyraising conversion precision at the time of secondary conversion.However, the same advantageous effect can be obtained by attaching onlythe renewal frame data Ib to the user's bit area 20. In the same manner,the same advantageous effect can be obtained by attaching only thesequence number data Id to the user's bit area 20.

Furthermore, the area to which the sequence number data Id or therenewal frame data Ib is attached is not limited to the user's bit area20. Needless to say, the area may be any signal area if, in time codesignals (LTC signals), these data can be attached thereto.

INDUSTRIALLY APPLICABILITY

According to the present invention, an error generated duringtransmission of time code signals can be effectively detected.

1. A time code signal transmitting method, comprising: the step ofreading a check-receiving data included in a transmitted time codesignal and using the read check-receiving data to generate atransmitting side checking data, the step of attaching the transmittingside checking data to the transmitted time code signal, the step ofreading the check-receiving data from the received time code signal andusing the read check-receiving data to generate a receiving sidechecking data, as a post-processing step after the time code signal isreceived, and the step of reading the transmitting side checking datafrom the received time code signal and comparing the read transmittingside checking data to the receiving side checking data, therebyverifying whether or not an error is generated in the received time codesignal as a pre-processing step at the time of transmitting the timecode signal.
 2. The time code transmitting method according to claim 1,wherein the transmitted time code signal is a single time code signal.3. The time code signal transmitting method according to claim 2,wherein the transmitted single time code signal is an LTC (linear timecode) signal.
 4. The time code signal transmitting method according toclaim 1, wherein there is used a data recorded on a user's bit area forthe time code signal as the check-receiving data to attach the checkingdata to the user's bit area for the time code signal.
 5. The time codesignal transmitting method according to claim 1, wherein the time codesignal is a time code signal corresponding to a picture signal to whichformat conversion in which a change in the number of frames per secondis generated is applied.
 6. The time code signal transmitting methodaccording to claim 5, wherein the time code signal is a signal to whicha data on the format conversion is attached.
 7. A time code signaltransmitting device, comprising a transmitting device for transmitting atime code signal, and a receiving device for receiving the time codesignal transmitted by the transmitting device, wherein the transmittingdevice comprises: a transmitting side checking data generator forreading a check-receiving data included in the transmitted time codesignal and using the read check-receiving data to generate atransmitting side checking data, and an attaching unit for attaching thetransmitting side checking data to the transmitted time code signal, andthe receiving device comprises: a receiving side checking data generatorfor reading the check-receiving data from the received time code signaland using the read check-receiving data to generate a receiving sidechecking data, and a verifying unit for reading the transmitting sidechecking data from the received time code signal and comparing the readtransmitting side checking data to the receiving side checking data,thereby verifying whether or not an error is generated in the receivedtime code signal.
 8. The time code transmitting device according toclaim 7, wherein the transmitted time code signal is a single time codesignal.
 9. The time code signal transmitting device according to claim8, wherein the transmitted single time code signal is an LTC (lineartime code) signal.
 10. The time code signal transmitting deviceaccording to claim 7, wherein the transmitting side checking datagenerator is a unit for reading the check-receiving data from a use'sbit area for the time code signal, and the attaching unit is a unit forattaching the transmitting side checking data to the user's area for thetime code signal.
 11. The time code signal transmitting device accordingto claim 7, wherein the time code signal is a time code signalcorresponding to a picture signal to which format conversion in which achange in the number of frames per second is generated is applied. 12.The time code signal transmitting device according to claim 11, whereinthe time code signal is a signal to which a data on the formatconversion is attached.